Today the HDMI Forum announced a big upgrade to their video connectivity standard: HDMI 2.0. What does this mean for this autumn’s ’4K’ Mac Pro?
HDMI 2.0: 4K and more
HDMI (High Definition Media Interface) is a successful video and audio interface standard that has been used in over 3 billion devices since 2003. It is used to transfer uncompressed video and audio from one device to another.
The initial definition defined a maximum video resolution over a single connection of 1920×1200 at 60 frames a second with 24 bits used to represent each pixel, using a maximum throughput of 4.95 Gbit/s.
Today’s 2.0 definition includes the following specifications:
- Maximum resolution: 4096 x 2160 p 60 48 bits/pixel
- Maximum audio channels: 32
- Maximum audio sample frequency: 1536kHz
- Simultaneous delivery of multi-stream audio to up to 4 users
- Support for 21:9 aspect ratio
- Maximum throughput: 18 Gbit/s
The cables and connectors haven’t changed, the definition of the data that can be transmitted along the wires has changed.
Apple and HDMI 2.0
Apple is a member of The HDMI Forum, so what does 2.0 mean for Apple products?
In June Apple previewed this year’s new Mac Pro. Many were surprised that Apple included six Thunderbolt 2 ports and an HDMI 1.4 connection. Firstly, Thunderbolt 2 had only been announced a few days before by Intel with the first products using the new standard expected in 2014. Secondly, given that Apple said that the Mac Pro is designed to be a full 4K editing device, why include an HDMI port that can only handle 24 frames a second at 4K?
HDMI 2.0 could explain some of the Mac Pro specification. Thunderbolt 2 is implemented using Intel’s Falcon Ridge I/O controller. It doubles the possible maximum throughput of the connection in one direction from 10 Gbit/s to 20 Gbit/s.
Currently Apple’s Mac Pro page states that it will have an HDMI 1.4 connector. As the I/O controller on the Mac Pro will be able to transfer up to of data 20 Gbit/s along Thunderbolt 2, maybe the HDMI port will be upgraded to 2.0 on launch day to transfer up to 18 Gbit/s of video and audio. HDMI 2.0 is electrically identical to HDMI 1.4: the wires and ports are the same. It’s probably a matter of upgrading the firmware in the I/O controller. The HDMI site says that ‘The HDMI 2.0 Compliance Test Specification is expected to be released before the end of 2013.’
It also allows Apple to launch a range of 4K monitors that use HDMI 2.0 data standards. Knowing Apple however, they may transmit the HDMI video and audio signals along a special Apple-flavoured Thunderbolt 2 cable instead of using standard HDMI connectors and cables.
HDMI 2.0 might mean there’s more to the Mac Pro’s 4K ambitions than Thunderbolt 2 and a new version of Final Cut Pro X.